meaning of "Formed on"

[ivyss]

Test No. incompl/inter-31 "Life on Mars?", question 3

It seems that Mars has always been cold and icy and that it's not true that oceans have ......... on the planet in its early history.

(a) shaped
(b) figured
(c) contoured
(d) formed

Test No. incompl/inter-31 "Life on Mars?", answer 3

It seems that Mars has always been cold and icy and that it's not true that oceans have formed on the planet in its early history.

Correct answer: (d) formed

Your answer was: incorrect
It seems that Mars has always been cold and icy and that it's not true that oceans have figured on the planet in its early history.
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why is form but not the other words? could you explain thanks a lot.
is 'form on' a fix phrase?

ivyss

[Mister Micawber]

.
Formed on is not a fixed phrase. Form here means come into existence. The other three choices do not offer meaningful verbs in this sentence, though amendation could include them:

Oceans have been shaped on the planet
Oceans have figured in the history of the planet
Oceans have been countoured by the planet's history
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber

[lost_soul]

What bothers me is why you used the present perfect to describe an event taken place in the past: